At a Glance
- Researchers from Southeast University in China have developed a supercool cement that can passively cool buildings by reflecting sunlight and radiating heat away from the structure.
- The material features a metasurface of self-assembled reflective ettringite crystals and hierarchical pores, achieving 96.2% solar reflectance and 96.0% mid-infrared emissivity.
- During midday testing, the photonic-architected cement demonstrated a remarkable temperature drop of 5.4 degrees Celsius compared to the surrounding air under intense solar radiation.
- This advanced cement exhibits high strength, armored abrasive resistance, and optical stability, even when subjected to harsh environmental conditions like UV radiation and freeze-thaw cycles.
- A machine learning-guided life-cycle assessment suggests this innovative material has the potential to achieve a net-negative carbon emission profile over a 70-year operational period.
Scientists have developed an innovative “supercool” cement that can passively cool buildings, potentially slashing energy costs and reducing the construction industry’s carbon footprint. In a world where air conditioning accounts for a significant portion of global energy consumption, this breakthrough by a team led by researchers at Southeast University in China offers a sustainable solution to keeping our buildings comfortable. The research, detailed in the journal Science Advances, presents a new building material that could transform how we approach cooling in an increasingly warm climate.
The new material works by fundamentally changing cement from a heat absorber into a heat reflector. Standard cement soaks up infrared radiation from the sun, storing it as heat and warming buildings from the outside in. To counter this, the research team engineered a material that performs passive daytime radiative cooling (PDRC), a process that involves reflecting sunlight and efficiently radiating heat back into space. They accomplished this by creating a unique “metasurface” on the cement. During a low-carbon production process, tiny, reflective crystals of a mineral called ettringite self-assemble on the surface, which, combined with a network of hierarchical pores, gives the cement an extremely high solar reflectance of 96.2%. This structure reflects sunlight as a mirror and radiates heat.
To validate their creation, the scientists put the supercool cement to the test on a rooftop at Purdue University. Under a midday sun with a solar intensity of 850 watts per square meter, the cement’s surface registered 5.4 degrees Celsius cooler than the surrounding air temperature. Beyond its cooling power, the cement was designed for real-world civil engineering applications. It underwent rigorous testing and demonstrated high strength, excellent resistance to abrasion, and optical stability, maintaining its cooling properties even after exposure to corrosive liquids, ultraviolet radiation, and damaging freeze-thaw cycles.
The long-term environmental implications of this technology could be profound. A life-cycle assessment guided by machine learning predicted that the supercool cement has the potential to achieve a net-negative carbon emission profile over a 70-year lifespan. “We have innovatively transformed cement materials from heat absorbers to heat reflectors using a bottom-up approach,” the researchers stated. This shift could help pivot the massive cement industry toward a more sustainable, energy-efficient future, creating healthier and more pleasant urban environments while combating climate change.
References
- Arnold, P. & Phys.org. (2025, August 21). Novel cement lets buildings cool themselves. Tech Xplore; Phys.org. https://techxplore.com/news/2025-08-cement-cool.html
- Lu, G., Du, F., Wang, Z., Wu, F., Zuo, W., Xu, X., Wu, Z., Liu, C., Yang, R., Tian, Y., Hu, Z., Zhao, D., Guo, C., Li, T., She, W., & Miao, C. (2025). Scalable metasurface-enhanced supercool cement. Science Advances, 11(34), eadv2820. https://doi.org/10.1126/sciadv.adv2820
